This invention relates to a cover, particularly for sealing an opening of a housing from which a shaft or rod projects. The housing cover is of the type which includes a main body of profiled cross section which may have bolt openings and which has a dynamic sealing zone about the central cover aperture through which the shaft or rod passes. The dynamic sealing zone is thus arranged concentrically with respect to the shaft or rod. The main body further has at least one, essentially flat sealing zone lying in a plane other than that in which the dynamic sealing zone is situated. Both sealing zones are provided with sealng elements.
In an article entitled "Motor und Kurbelwelle als Schwingungssystem und ihr Einfluss auf die Kurbelwellen-Dichtungen" ("Engine and Crankshaft as an Oscillating System and their Effect on Crankshaft Seals") in the periodical Motortechnische Zeitschrift (Issue 42 of July/August 1981, pages 285-289) a cover of the above-outlined type is described. The cover has, in the zone of its inner circumferential surface, a dynamic sealing zone formed of a conventional shaft seal ring as well as a static sealing zone which is situated in the outer circumferential surface and which is formed by an O-ring. The cover is mounted on a housing, such as a crankcase, by means of bolts or the like.
The above-outlined conventional sealing cover has several disadvantages. Thus, because individual structural components have to be assembled together, the mounting operation is highly labor-intensive. Further, the sealing components cannot be reliably prevented from slipping out of their intended seat or from undergoing twists which would cause leakages. Since particularly crankcase covers are, for the purpose of saving weight, in most cases made of a light metal and have relatively thin walls, the use of a conventional flat seal in the zone of the end faces of the cover does not fully serve its intended purpose, because the clearance to be sealed between the cover and the housing does not have constant dimensions.
German Offenlegungsschrift (application published without examination) No. 2,822,615 discloses a rod seal for shock absorbers, comprising a dynamic and a static sealing range connected to one another by channels. Both sealing ranges are of circumferential course and serve for seating elastic sealing elements which sealingly engage circumferential faces of a shaft and a shock absorber tube. While in this structure a possibility of connection between the two sealing zones is provided, it cannot find application in covers having sealing zones arranged in different radial and axial planes and further, the channels do not have any sealing function.